1. Field of the Invention
The present invention relates to a data management technique.
2. Description of the Related Art
In recent years, apparatuses which generate digital data such as personal computers (PCs), digital still cameras, digital video cameras, hard disk recorders, and the like have rapidly prevailed. In addition, since improvement of the inter-connectability of apparatuses via a network, development of the data distribution channels such as e-mail that distribute digital data, and the high-speed Internet and intranet, and an increase in capacity of storage devices in PCs, hard disk recorders, portable music players, and the like used to store digital data have progressed, various apparatuses around us store large amounts and a wide variety of digital data. In this way, in circumstances in which various apparatuses store large amounts of data, it becomes difficult to efficiently search for target data.
In contrast, a method of classifying data based on auxiliary information of data, for example, information such as the dates of creation, types of data, sizes of data, titles, and the like (these pieces of information are called “metadata”, items such as the dates of creation, types, sizes, and the like are called “metadata items,” and values set for these items are called “metadata values”), holding data together in folders and the like for respective metadata items, and hierarchically laying out and displaying these folders has been devised. In this method, the user can search for required data by tracing the hierarchically laid-out folders (called folder hierarchy) without working out complicated search formulas.
However, even when the predetermined folder hierarchy is one-sidedly presented, they may often not have a structure that the user intended, and it is not so efficient to search for data by tracing such a folder hierarchy.
Hence, a method which allows the user to designate the order of layers of the folders which hold data together for respective metadata items, and helps the user form the intended folder hierarchy has been proposed (see Japanese Patent Laid-Open No. 2000-250798).
However, the method disclosed in Japanese Patent Laid-Open No. 2000-250798 provides means for forming folder hierarchy that reflects the user's intention, but the user must decide the hierarchical relationship of metadata items in a trial and error manner, and the user still bears a heavy burden. Depending on the data to be handled, the display system of the folder hierarchy that the user requires may change. However, there is no mechanism to form the folder hierarchy that can follow such changes.